I have a 10m2 room in the garage intended as a guest/hobby room, I've insulated and plastered.
Now I've started to consider if I should add a bit more insulation.
Today I have 140mm.
Does it make a big difference in heating costs if I frame up and add an extra 45 or 70 mm?
And can it be done directly against the plasterboard that is there today?
I want it to be 19 degrees year-round!
